Apparatus and method for dry distillation of oil shale

ABSTRACT

An apparatus for dry distillation of oil shale, has a vibration bed with multiple layers, a gas retort, a feeding system, a feeding hole, a screen plate, a water seal tank, a discharging system, and a gas outlet. The feeding system and the feeding hole are disposed at the top of the gas retort. The screen plate is disposed on the vibration bed. The layers of the vibration bed are obliquely disposed in the gas retort. The number of layers of the vibration bed is nine. Three hot recycle gas inlets are disposed on the wall of the gas retort and respectively below the fourth layer, the fifth layer and the sixth layer of the vibration bed. A cold recycle gas inlet is disposed below the ninth layer of the vibration bed. The water seal tank and the discharging system are disposed at the bottom of the gas retort. The gas outlet is disposed at the top of the gas retort. The apparatus features a simple structure, convenient operation, low cost, and a high oil recovery and resource unitization rate.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. §119 and the Paris Convention Treaty, this application claims the benefit of Chinese Patent Application No. 200810013072.4 filed on Sep. 3, 2008, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an apparatus and a method for dry distillation of oil shale.

2. Description of the Related Art

Oil shale are widely distributed throughout the world and become of economic interest because of the large amounts of oil which can be obtained from them. Conventional apparatuses for dry distillation of oil shale comprise a petrosix retort, an alberta taciuk processor (ATP) retort and so on. However, there are several problems with these apparatuses: they have complex structure, inconvenient operation, high investigation cost, low oil recovering rates, and poor resource utilization rates. Moreover, the same problems as above are encountered with conventional methods for dry distillation of oil shale.

SUMMARY OF THE INVENTION

In view of the above-described problems, it is one objective of the invention to provide a method for dry distillation of oil shale that features a simple structure, convenient operation, low investigation cost, a high oil recovering rate, and a high resource utilization rate.

It is another objective of the invention to provide an apparatus for dry distillation of oil shale that features a simple structure, convenient operation, low investigation cost, a high oil recovering rate, and a high resource utilization rate.

To achieve the above objective, in accordance with one embodiment of the invention, provided is a method for dry distillation of oil shale, comprising inducing oil shale from the top of a gas retort and dispersing the oil shale into Z-shaped, flat and loose material flow via a vibration bed with multiple layers, part of the oil shale having granularity less than screen holes dropping via the screen holes and forming a dilute phase layer with oil shale blown up from the next layer, the rest of the oil shale having granularity greater than the screen holes forming a loose material layer that moves along a screen plate and drops on the next screen plate, leading hot recycle gas at a temperature of 700° C. into the gas retort from the bottom of the fourth, the fifth, and the sixth layer of the vibration bed whereby forming vertical airflow and horizontal airflow, mixing the vertical airflow and the horizontal airflow with the oil shale whereby generating mixing flow of the oil shale and the gas, leading cold recycle gas from the bottom of the gas retort and cooling semi coke that has been dry distilled to 250° C., dropping the semi coke into a water seal tank, cooling it to 80° C. and discharging it via a discharging system disposed at the bottom of the gas retort, discharging dry distillation gas and recycle gas from the top of the gas retort and transmitting them to a heating furnace after removing dust and recovering oil, and heating the dry distillation gas to 700° C. via a heating furnace and transferring it to the gas retort.

In a class of this embodiment, granularity of the oil shale is below 12 mm

In a class of this embodiment, granularity of the oil shale is below 6 mm.

In a class of this embodiment, a height of each of the third layer, the fifth layer, and the sixth layer of the vibration bed is 4.5 m-5 m.

In a class of this embodiment, the third layer, the fifth layer, and the sixth layer of the vibration bed are dry distillation sections.

In a class of this embodiment, moving speeds of oil shale on different layers are varied by adjusting a motor frequency of each layer of the vibration bed.

In a class of this embodiment, time of keeping materials in the gas retort is varied by adjusting a motor frequency of each layer of the vibration bed.

In accordance with another embodiment of the invention, provided is an apparatus for dry distillation of oil shale, comprising a vibration bed with multiple layers, a gas retort, a feeding system, a feeding hole, a screen plate, a water seal tank, a discharging system, and a gas outlet, wherein the feeding system and the feeding hole are disposed at the top of the gas retort, the screen plate is disposed on the vibration bed, the layers of the vibration bed are obliquely disposed in the gas retort, the number of layers of the vibration bed is nine, three hot recycle gas inlets are disposed on the wall of the gas retort and respectively below the fourth layer, the fifth layer and the sixth layer of the vibration bed, a cold recycle gas inlet is disposed below the ninth layer of the vibration bed, the water seal tank and the discharging system are disposed at the bottom of the gas retort, and the gas outlet is disposed at the top of the gas retort.

In a class of this embodiment, the obliquely disposed layers of the vibration bed form a Z-shaped structure.

A key point of the invention is that the vibration bed with nine layers is used to transport oil shale, and fully contacted with the hot recycle gas during the transportation process whereby facilitating dry distillation. To implement the dry distillation processing, the following techniques are used: firstly, movement of the oil shale is in the manner of vibration caused by gravity thereof and driving force applied by vibration. A Z-shaped material flow is formed in the gas retort. A height of the gas retort is approximately 17 m, and a travel distance of the oil shale is approximately 36 m. Secondly, a mixing flow technique is used, contact between hot gas and the oil shale is horizontal and vertical, contact between the oil shale and the screen plate exists or does not exist, and the material layer is always loose, which ensures hot carriers are fully contacted with the oil shale. Thirdly, hot gas are induced from three layers of the vibration bed, which ensures temperature in the gas retort is above 550° C. and a height of a dry distillation layer is between 4.5 m and 5 m, and guarantees safety of the dry distillation process. Fourthly, moving speeds of oil shale on different layers and time of keeping materials in the gas retort are varied by adjusting a motor frequency of each layer of the vibration bed, which makes operation convenient. Fifthly, a full recycle process of hot gas is used, heating of gas is performed outside the gas retort and no heating process occurs therein, no air enters therein, and heat needed by the dry distillation process is completely dependent on the hot recycle gas, which improves a calorific value of the gas and that of the semi coke. Sixthly, cold recycle gas is induced from the bottom of the gas retort and reduces temperature of the semi coke that is dry distillated. Finally, a water seal scraping plate is disposed at the bottom of the gas retort to facilitate coke discharging, which prevents gas from leaking and protects the environment.

Advantages of the invention comprise:

1. The invention features simple structure and convenient operation. A traditional gas retort covers an area above 1000 m², and the gas retort of the invention only covers no more than 100 m². The traditional gas retort is complex in structure and inconvenient for operation. The invention facilitates variation of moving speeds of oil shale by adjusting frequencies of motors, which makes the invention simple in structure and convenient for operation;

2. The invention features a high oil recovering rate and a high gas calorific value. Since a full recycle process of gas is used, a special mixing flow is formed by vertical airflow, horizontal airflow, forward flow, and reverse flow between the oil shale and the hot gas, and features no air, no heating reaction, a high oil recovering rate above 90%, and a gas calorific value above 4000 kcal/kg;

3. The invention features low investigation cost and a high efficiency, The conventional gas retort normally spends 1.5 billion US dollars and seven years, and the invention only spends no more than 100 million US dollars;

4. The invention features a high resource utilization rate of 100%, oil shale having granularity less than 12 mm can be used as raw materials, and new exploited oil shale can be broken into oil shale having granularity less than 6 mm for dry distillation; and

5. A water seal scraping plate is disposed at the bottom of the gas retort to facilitate coke discharging, which prevents gas from leaking and protects the environment.

In a class of this embodiment, the step of applying force on the polycrystalline silicon rods so that the polycrystalline silicon rods are detached from the base plate and fall into the cavity comprises applying force on the polycrystalline silicon rods via a contact, passing a wall of the harvest equipment by the contact, applying force on the polycrystalline silicon rods so that they are detached from the base plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed description of the invention will be given below with reference to accompanying drawings, in which:

FIG. 1 is a schematic view of an apparatus for dry distillation of oil shale of an exemplary embodiment of the invention; and

FIG. 2 is a cross-sectional view of an apparatus for dry distillation of oil shale of an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1 and 2, a method for dry distillation of oil shale of the invention comprises inducing oil shale from a bucket 2 at the top of a gas retort 4 and dispersing the oil shale into Z-shaped, flat and loose material flow via a vibration bed 3 with multiple layers, part of the oil shale having granularity less than screen holes dropping via the screen holes and forming a dilute phase layer with oil shale blown up from the next layer, the rest of the oil shale having granularity greater than the screen holes forming a loose material layer that moves along a screen plate and drops on the next screen plate, leading hot recycle gas at a temperature of 700° C. into the gas retort 4 from the bottom of the fourth, the fifth, and the sixth layer of the vibration bed 3 via hot recycle gas inlets 5, 10 and 11 whereby forming vertical airflow and horizontal airflow, mixing the vertical airflow and the horizontal airflow with the oil shale whereby generating mixing flow of the oil shale and the gas, leading cold recycle gas from the bottom of the gas retort 4 and cooling semi coke that has been dry distilled to 250° C., dropping the semi coke into a water seal tank 7, cooling it to 80° C. and discharging it via a discharging system 8 disposed at the bottom of the gas retort 3, discharging dry distillation gas and recycle gas from the top of the gas retort 4, mixing the oil shale with the gas, separating the oil shale from the gas, remixing the oil shale with gas, and re-separating the oil shale from the gas whereby uniformly dry distilling the oil shale, cooling the oil shale via the cold gas induced from the bottom of the gas retort 4 and the and water seal tank 7, dropping the oil shale into the discharging system 8, discharging the oil shale from the bottom of the gas retort 4, discharging dry distillation gas and recycle gas from the top of the gas retort 4 with the recycle gas, transmitting them to a heating furnace after removing dust and recovering oil, and heating the dry distillation gas to 700° C. via a heating furnace and transferring it to the gas retort.

In this embodiment, a height of each of the third layer, the fifth layer, and the sixth layer of the vibration bed 3 is 4.5 m-5 m.

In this embodiment, granularity of the oil shale is below 12 mm or 6 mm.

The third layer, the fifth layer, and the sixth layer of the vibration bed 3 are dry distillation sections.

Moving speeds of oil shale on different layers and time of keeping materials in the gas retort 3 are varied by adjusting a motor frequency of each layer of the vibration bed.

As shown in FIGS. 1 and 2, an apparatus for dry distillation of oil shale of the invention comprises a vibration bed 3 with multiple layers, a gas retort 4, a feeding system 1, a feeding hole, a screen plate, a water seal tank 7, a discharging system 8, and a gas outlet 12.

The feeding system 1 and the feeding hole are disposed at the top of the gas retort 4.

The screen plate is disposed on the vibration bed 3.

The layers of the vibration bed 3 are obliquely disposed in the gas retort 4.

The number of layers of the vibration bed 3 is nine, and three hot recycle gas inlets 5, 10 and 11 are disposed on the wall of the gas retort 4 and respectively below the fourth layer, the fifth layer and the sixth layer of the vibration bed 3.

A cold recycle gas inlet 6 is disposed below the ninth layer of the vibration bed 3.

The water seal tank 7 and the discharging system 8 are disposed at the bottom of the gas retort 4.

The gas outlet 12 is disposed at the top of the gas retort 4.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. 

1. A method for dry distillation of oil shale, comprising inducing oil shale from the top of a gas retort and dispersing said oil shale into Z-shaped, flat and loose material flow via a vibration bed with multiple layers, part of said oil shale having granularity less than screen holes dropping via said screen holes and forming a dilute phase layer with oil shale blown up from the next layer, the rest of said oil shale having granularity greater than said screen holes forming a loose material layer that moves along a screen plate and drops on the next screen plate; leading hot recycle gas at a temperature of 700° C. into said gas retort from the bottom of the fourth, the fifth, and the sixth layer of said vibration bed whereby forming vertical airflow and horizontal airflow; mixing said vertical airflow and said horizontal airflow with said oil shale whereby generating mixing flow of said oil shale and said gas; leading cold recycle gas from the bottom of said gas retort and cooling semi coke that has been dry distilled to 250° C.; dropping said semi coke into a water seal tank, cooling it to 80° C. and discharging it via a discharging system disposed at the bottom of said gas retort; discharging dry distillation gas and recycle gas from the top of said gas retort and transmitting them to a heating furnace after removing dust and recovering oil; and heating the dry distillation gas to 700° C. via a heating furnace and transferring it to said gas retort.
 2. The method for dry distillation of oil shale of claim 1, wherein granularity of said oil shale is below 12 mm.
 3. The method for dry distillation of oil shale of claim 1, wherein granularity of said oil shale is below 6 mm.
 4. The method for dry distillation of oil shale of claim 1, wherein a height of each of said fourth layer, said fifth layer, and said sixth layer of said vibration bed is 4.5 m-5 m.
 5. The method for dry distillation of oil shale of claim 1, wherein said fourth layer, said fifth layer, and said sixth layer of said vibration bed are dry distillation sections.
 6. The method for dry distillation of oil shale of claim 1, wherein moving speeds of oil shale on different layers are varied by adjusting a motor frequency of each layer of said vibration bed.
 7. The method for dry distillation of oil shale of claim 1, wherein time of keeping materials in said gas retort is varied by adjusting a motor frequency of each layer of said vibration bed
 8. An apparatus for dry distillation of oil shale, comprising a vibration bed (3) with multiple layers; a gas retort (4); a feeding system (1); a feeding hole; a screen plate; a water seal tank (7); a discharging system (8); and a gas outlet (12); wherein said feeding system (1) and said feeding hole are disposed at the top of said gas retort (4); said screen plate is disposed on said vibration bed (3); said layers of said vibration bed are obliquely disposed in said gas retort (4); the number of layers of said vibration bed (3) is nine; three hot recycle gas inlets (5), (10) and (11) are disposed on the wall of said gas retort (4) and respectively below the fourth layer, the fifth layer and the sixth layer of said vibration bed (3); a cold recycle gas inlet (6) is disposed below the ninth layer of said vibration bed (3); said water seal tank (7) and said discharging system (8) are disposed at the bottom of said gas retort (4); and said gas outlet (12) is disposed at the top of said gas retort (4).
 9. The apparatus for dry distillation of oil shale of claim 1, wherein the obliquely disposed layers of said vibration bed (3) form a Z-shaped structure. 